1 Have you seen a reef? A reef is made with stone and coral. Many animals and plants live in it. A reef is like a little world.2 A reef looks strong, but it is not. Coral is formed by tiny animals. They have soft bodies. Some make hard covers for their bodies. The cover is a kind of calcium [CAL-see-um]. It is what a hen's egg shell is made of.3 The corals that make the covers for their bodies are hard corals. They do not move with the water.4 The other kind is the soft coral. They do not make hard covers. They bend and sway in the water.5 Corals do not have their own color. They live with algae [AL-gee]. The algae give them color.6 Corals need to grow in shallow water. They also need clean water.7 If the water were dirty, it would cover the coral. The coral animals could not breathe. They would die.8 Other animals live at the reef, too. Did you know that the sponge is an animal?9 Reef fish have many colors. They are often in bright, bold colors. They also come in spots and stripes. They also come in many sizes.